Backhaul management of a small cell using passive estimation mechanism

ABSTRACT

The present disclosure presents a method and an apparatus for passive estimation mechanism for backhaul management at a small cell base station. For example, the method may include determining, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow, determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold, and identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold. As such, passive estimation mechanism for backhaul management at a small cell base station may be achieved.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present application for patent claims priority to U.S. Provisional Application No. 61/897,064, filed Oct. 29, 2013, entitled “Backhaul Aware Load Management for Small Cells—Passive Estimation,” U.S. Provisional Application No. 61/897,061, filed Oct. 29, 2013, entitled “Backhaul Estimation for Small Cells—Calibration,” U.S. Provisional Application No. 61/897,069, filed Oct. 29, 2013, entitled “Backhaul Estimation for Small Cells—Light Active Estimation,” U.S. Provisional Application No. 61/897,114, filed Oct. 29, 2013, entitled “Method and Apparatus for Backhaul Congestion Estimation Using Heavy Active Probing for Small Cells,” U.S. Provisional Application No. 61/897,098, filed Oct. 29, 2013, entitled “Apparatus and Method for Off-Loading User Equipment from a Small Cell,” U.S. Provisional Application No. 61/933,732, filed Jan. 30, 2014, entitled “Backhaul Management of a Small Cell,” all assigned to the assignee hereof and hereby expressly incorporated by reference herein.

BACKGROUND

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to backhaul estimation for small cells and the like.

Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. In cellular networks, macro base stations (or macro cells or conventional base stations) provide connectivity and coverage to a large number of users over a certain geographical area. To supplement macro base stations, restricted power or restricted coverage base stations, referred to as small coverage base stations or small cell base stations or small cells, can be deployed to provide more robust wireless coverage and capacity to mobile devices. In this way, the deployment of small cell base stations may provide incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and so on. However, the deployment of small cell base stations may also encroach on the operation of other devices that typically utilize the same space, such as Wireless Local Area Network (WLAN) devices operating in accordance with one of the IEEE 802.11x communication protocols (so-called “Wi-Fi” devices) or other wired or wireless devices sharing the same Internet connection in a user's residence or office building. The unmanaged sharing of common backhaul resources may lead to various throughput and/or data integrity problems for all devices.

When a small cell is deployed with a backhaul of variable quality or where the backhaul is shared with other devices, the quality of the backhaul has to be monitored to provide reliable service to devices in communication with the small cell (e.g., UEs). This monitoring may allow a small cell operator to offer a good perceived Quality of Service (QoS) to a user and take action (e.g., hand out UE to a macro cell) to maintain QoS when the backhaul quality degrades. But if UEs have to be repeatedly offloaded from the small cell (e.g., handed out to a macro cell) due to backhaul conditions, the Quality of Experience (QoS) of UEs may suffer. Additionally, if QoS of UEs is limited due to the inability of radio resource management (RRM) of the small cell to hand out the UEs to macro cells, backhaul estimation mechanisms may unnecessarily consume resources such as, for example, network and/or processor resources.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects not delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

The present disclosure presents an example method and apparatus for passive estimation mechanism for backhaul management at a small cell base station. For example, the present disclosure presents an example method for passive estimation mechanism for backhaul management at a small cell base station that may include determining, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow, determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold, and identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

Additionally, the present disclosure presents an example apparatus for passive estimation mechanism for backhaul management at a small cell base station that may include means for determining, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow, means for determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold, and means for identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

In a further aspect, the presents disclosure presents an example non-transitory computer readable medium for passive estimation mechanism for backhaul management at a small cell base station comprising code that, when executed by a processor or processing system included within the small cell base station, causes the small cell base station to determine, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow, determine whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold, and identify that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

Furthermore, in an aspect, the present disclosure presents an example apparatus for passive estimation mechanism for backhaul management at a small cell base station that may include a time slot utilization determiner to determine whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow, an average throughout determiner to determine whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold, and a flow satisfaction identifier to identify that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of an example of an access network in which the present aspects may be implemented;

FIG. 2 is a conceptual diagram of an example communication network environment in which the present aspects may be implemented;

FIG. 3 is a conceptual diagram of another example of a communication network environment in which the present aspects may be implemented;

FIG. 4 is a flow diagram providing an overview of various aspects of backhaul estimation as contemplated by the present disclosure;

FIG. 5 is a flow diagram of an example method for passive estimation mechanism for backhaul management at a small cell base station;

FIG. 6 is a block diagram of an example BALM component in aspects of the present disclosure;

FIG. 7 is a block diagram of an example of a NodeB in communication with a UE in a telecommunications system in which the present aspects may be implemented; and

FIG. 8 is a block diagram of an example of a small cell apparatus, represented as a series of interrelated functional modules, according to a present aspect.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known components are shown in block diagram form in order to avoid obscuring such concepts.

The present disclosure presents a method and apparatus for passive estimation mechanism for backhaul management at a small cell base station. The passive estimation mechanism includes determining, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow, determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold, and identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

As used herein, the term “small cell” may refer to an access point or to a corresponding coverage area of the access point, where the access point in this case has a relatively low transmit power or relatively small coverage as compared to, for example, the transmit power or coverage area of a macro network based station or macro cell. For instance, a macro cell may cover a relatively large geographic area, such as, but not limited to, several kilometers in radius. In contrast, a small cell may cover a relatively small geographic area, such as, but not limited to, a home, a building, or a floor of a building. As such, a small cell may include, but is not limited to, an apparatus such as a base station (BS), an access point, a femto node, a femtocell, a pico node, a micro node, a wireless relay station, a Node B, evolved Node B (eNB), home Node B (HNB) or home evolved Node B (HeNB). Therefore, the term “small cell,” as used herein, refers to a relatively low transmit power and/or a relatively small coverage area cell as compared to a macro cell.

FIG. 1 illustrates an example wireless communication network 100 demonstrating multiple access communications, and in which the present aspects may be implemented. The illustrated wireless communication network 100 is configured to support communication among a numbers of users. As shown, the wireless communication network 100 may be divided into one or more cells 102, such as the illustrated cells 102A-102G. Communication coverage in cells 102A-102G may be provided by one or more base stations 104, such as the illustrated base stations 104A-104G. In this way, each base station 104 may provide communication coverage to a corresponding cell 102. The base station 104 may interact with a plurality of user devices 106, such as the illustrated user devices 106A-106L.

Each user device 106 may communicate with one or more of the base stations 104 on a downlink (DL) and/or an uplink (UL). In general, a DL is a communication link from a base station to a user device, while an UL is a communication link from a user device to a base station. The base stations 104 may be interconnected by appropriate wired or wireless interfaces allowing them to communicate with each other and/or other network equipment. Accordingly, each user device 106 may also communicate with another user device 106 through one or more of the base stations 104. For example, the user device 106J may communicate with the user device 106H in the following manner: the user device 106J may communicate with the base station 104D, the base station 104D may then communicate with the base station 104B, and the base station 104B may then communicate with the user device 106H, allowing communication to be established between the user device 106J and the user device 106H.

The wireless communication network 100 may provide service over a large geographic region. For example, the cells 102A-102G may cover a few blocks within a neighborhood or several square miles in a rural environment. In some systems, each cell may be further divided into one or more sectors (not shown). In addition, the base stations 104 may provide the user devices 106 access within their respective coverage areas to other communication networks, such as the Internet or another cellular network. Each user device 106 may be a wireless communication device (e.g., a mobile phone, router, personal computer, server, etc.) used by a user to send and/or receive voice and/or data over a communications network, and may be alternatively referred to as an Access Terminal (AT), a Mobile Station (MS), a User Equipment (UE), etc. In the example shown in FIG. 1, user devices 106A, 106H, and 106J comprise routers, while the user devices 106B-106G, 106I, 106K, and 106L comprise mobile phones. Again, however, each of the user devices 106A-106L may comprise any suitable communication device.

For their wireless air interfaces, each base station 104 may operate according to one of several Radio Access Technologies (RATs) depending on the network in which it is deployed, and may be alternatively referred to as a NodeB, evolved NodeB (eNB), etc. These networks may include, for example, Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, and so on. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a RAT such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a RAT such as Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (UMTS). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division—Code Division Multiple Access (TD-CDMA), and Time Division—Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of an emerging telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2).

In cellular networks, macro base stations (or macro cells or conventional base stations) provide connectivity and coverage to a large number of users over a certain geographical area. A macro cell network deployment is carefully planned, designed, and implemented to offer good coverage over the geographical region. Even such careful planning, however, cannot fully accommodate channel characteristics such as fading, multipath, shadowing, etc., especially in indoor environments. Indoor users therefore often face coverage issues (e.g., call outages and quality degradation) resulting in poor user experience. Further, macro cell capacity is upper-bounded by physical and technological factors.

Thus, as discussed above, small cell base stations may be used to provide significant capacity growth, in-building coverage, and in some cases different services than macro cells operating alone, thereby facilitating a more robust user experience.

FIG. 2 illustrates an example mixed communication network environment 200 in which small cell base stations (or small cells) are deployed in conjunction with macro cell base stations (or macro cells), and in which the present aspects may be implemented. As discussed above, small cell base stations may be used to provide significant capacity growth, in-building coverage, and in some cases different services than macro cells operating alone, thereby facilitating a more robust user experience.

In FIG. 2, a macro cell base station 205 may provide communication coverage to one or more user devices, for example, user equipment 220, 221, and 222, within a macro cell coverage area 230 (as discussed above in more detail with reference to FIG. 1), while small cell base stations 210 and 212 may provide their own communication coverage within respective small cell coverage areas 215 and 217, with varying degrees of overlap among the different coverage areas. It is noted that certain small cells may be restricted in some manner, such as for association and/or registration, and may therefore be referred to as Closed Subscriber Group (“CSG”) cells. In this example, at least some user devices, e.g., user equipment 222, may be capable of operating both in macro environments (e.g., macro areas) and in smaller scale network environments (e.g., residential, femto areas, pico areas, etc.) as shown.

Turning to the illustrated connections in more detail, user equipment 220 may generate and transmit a message via a wireless link to the macro cell base station 205, the message including information related to various types of communication (e.g., voice, data, multimedia services, etc.). User equipment 222 may similarly communicate with small cell base station 210 via a wireless link, and user equipment 221 may similarly communicate with small cell base station 212 via a wireless link. The macro cell base station 205 may also communicate with a corresponding wide area or external network 240 (e.g., the Internet), via a wired link or via a wireless link, while small cell base stations 210 and/or 212 may also similarly communicate with network 240, via their own wired or wireless links. For example, small cell base stations 210 and/or 212 may communicate with network 240 by way of an Internet Protocol (IP) connection, such as via a Digital Subscriber Line (DSL, e.g., including Asymmetric DSL (ADSL), High Data Rate DSL (HDSL), Very High Speed DSL (VDSL), etc.), a TV cable carrying IP traffic, a Broadband over Power Line (BPL) connection, an Optical Fiber (OF) cable, or some other link. This connection may utilize the existing backhaul infrastructure provided by, for example, an ISP for the residential home or office building in which small cells 210 and 212 are installed, and may accordingly be shared among other devices operating in the same environment, such as Wireless Local Area Network (WLAN) devices operating in accordance with one of the IEEE 802.11x communication protocols (so-called “Wi-Fi” devices) or other wired or wireless devices sharing the same Internet connection in a user's residence or office building.

Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3 GPP2).

The network 240 may comprise any type of electronically connected group of computers and/or devices, including, for example, the following networks: Internet, Intranet, Local Area Networks (LANs), or Wide Area Networks (WANs). In addition, the connectivity to the network may be, for example, by remote modem, Ethernet (IEEE 802.3), Token Ring (IEEE 802.5), Fiber Distributed Datalink Interface (FDDI) Asynchronous Transfer Mode (ATM), Wireless Ethernet (IEEE 802.11), Bluetooth (IEEE 802.15.1), or some other connection. As used herein, the network 240 includes network variations such as the public Internet, a private network within the Internet, a secure network within the Internet, a private network, a public network, a value-added network, an intranet, and the like. In certain systems, the network 240 may also comprise a Virtual Private Network (VPN).

Accordingly, it will be appreciated that macro cell base station 205 and/or either or both of small cell base stations 210 and 212 may be connected to network 240 using any of a multitude of devices or methods. These connections may be referred to as the “backbone” or the “backhaul” of the network, and may in some implementations be used to manage and coordinate communications between macro cell base station 205, small cell base station 210, and/or small cell base station 212. In this way, depending on the current location of user equipment 222, for example, user equipment 222 may access the communication network 240 by macro cell base station 205 or by small cell base station 210.

In an aspect, as used herein, the term “small cell base station” or “small cell” (e.g., small cell base station 320) may refer to an access point or to a corresponding coverage area of the access point, where the access point in this case has a relatively low transmit power or relatively small coverage as compared to, for example, the transmit power or coverage area of a macro network based station or macro cell. For instance, a macro cell may cover a relatively large geographic area, such as, but not limited to, several kilometers in radius. In contrast, a small cell may cover a relatively small geographic area, such as, but not limited to, a home, a building, or a floor of a building. As such, a small cell may include, but is not limited to, an apparatus such as a base station (BS), an access point, a femto node, a femtocell, a pico node, a micro node, a wireless relay station, a Node B, evolved Node B (eNB), home Node B (HNB) or home evolved Node B (HeNB). Therefore, the term “small cell,” as used herein, refers to a relatively low transmit power and/or a relatively small coverage area cell as compared to a macro cell. For example, small cells can be deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and/or the like. The small cell base stations may be connected to the Internet and/or a mobile operator's network via a digital subscriber line (DSL) router or a cable modem, for example, often utilizing the existing backhaul infrastructure provided by an Internet Service Provider (ISP) for the residential home or office building in which the small cell base station is installed.

FIG. 3 illustrates an example communication system 300 in which a small cell base station shares a backhaul connection with other wired and/or wireless devices, and in which the present aspects may be implemented. For example, a home router 302 is installed in a user residence 304 and provides access to the Internet 306 via an Internet service provider (ISP) 308. The home router 302 communicates (e.g., transfers user data and other signaling information) with ISP 308 via a modem 315 over a corresponding backhaul link 310. In an aspect, for example, the home router 302 may support various wired and/or wireless devices, such as a home computer 312, a wireless fidelity (Wi-Fi) enabled TV 314, etc. In an additional aspect, the home router 302 may include a wireless access point (AP), for example, a Wi-Fi access point (AP) providing connectivity to such devices. In an additional aspect, for example, the home router 302 may be integrated with a wireless access point Wi-Fi AP for providing connectivity to such devices.

In an aspect, a small cell base station (or a small cell) 320 is installed in user residence 304 and serves one or more nearby user equipments (UE) 322 as described above. The small cell base station 320 via its connection to home router 302 and shared backhaul link 310 may provide access to Internet 306 and core network 316. Since the backhaul link 310 is shared between the traffic managed by small cell 320 (e.g., native traffic) and traffic generated by other devices that home router 302 may be serving (e.g., cross traffic), there is a potential for congestion of uplink (UL) traffic, down link (DL) traffic, and/or both, with varying degrees of impact on the performance of the small cell and/or other devices sharing the backhaul link 310.

Accordingly, improved backhaul aware load management for small cell base stations operating in an increasingly crowded communication environment is needed. In an aspect, small cell base station 320 may be configured to include a backhaul-aware load management (BALM) component 324 operable to mitigate congestion on backhaul link 310. The operation of BALM component 324 may enable small cell base station 320 to determine various backhaul characteristics, for example, sustainable throughput, and corresponding delay and jitter variations, loss, etc., to identify backhaul congestion and/or take appropriate remedial actions. For example, in an aspect, when congestion is present, operation of BALM component 324 may enable small cell base station 320 via its radio resource management (RRM) module to offload one or more UEs 322 to a macro cell base station or otherwise reduce the coverage area of small cell base station 320 in order to reduce the number of UEs 322 being served. In an additional aspect, when congestion is present, operation of BALM component 324 may enable small cell base station 320 via its RRM module to offload one or more low throughput devices to a macro cell base station and/or reduce the coverage area of small cell base station 320 by lowering a pilot channel signal strength in order to reduce the number of UEs 322 being served. In an additional or optional aspect, operation of BALM component 324 may enable small cell base station 320 to limit the data rate of certain flows that are not backhaul-limited (e.g., by changing a video encoding rate). In a further additional or optional aspect, operation of BALM component 324 may enable small cell base station 320 to alert the user of one of the UEs 322 to enable the user of the UE to choose one of the above-noted actions and control the operation of the small cell. In an additional or optional aspect, the user of the UE may be alerted via a graphical user interface (GUI) to allow the user of the UE to choose one of the above-noted actions as described above.

FIG. 4 is a flow diagram 400 providing an overview of various BALM related procedures performed by a small cell base station via operation of BALM component 324. For example, in an aspect, a small cell base station (e.g., small cell base station 320 of FIG. 3) via operation of BALM component 324 may continually or periodically monitor throughput conditions of UEs supported (e.g., camped) by the small cell base station to determine if the throughput at the UE is sufficient or otherwise acceptable (e.g., naturally low-rate traffic, Internet peer limited, etc.). If the small cell base station via operation of BALM component 324 detects that the throughput appears to be insufficient and/or unacceptable, then the small cell base station via operation of BALM component 324 may then determine whether the underlying congestion is backhaul related, air link related, located in the UE's peer, and/or simply due to a low-rate application, and may take an appropriate action. For example, in an aspect, the determination may be based on whether the backhaul has unused capacity. If the small cell base station via operation of BALM component 324 detects that the backhaul has unused capacity, the backhaul may generally have no impact on the UE experiencing a low-throughput condition.

Referring in more detail to FIG. 4, in an aspect, for each UE (e.g., each of the UEs 322 in FIG. 3), a small cell base station (e.g., small cell base station 320 in FIG. 3) via operation of BALM component 324 may perform a light passive estimation procedure to determine if the existing throughput is sufficient for the UE (decision 402). For example, the determination may be made for both for the UL, DL, and/or both, either separately or together. If the existing throughput is sufficient (‘yes’ at decision 402), there is no congestion problem for the UE and the small cell base station continues to perform light passive estimation monitoring as appropriate, as described above.

In an aspect, if it is determined that the existing throughput is not sufficient (‘no’ at decision 402), the small cell base station via operation of BALM component 324 checks whether it is over-the-air (OTA) capacity that is limiting the throughput (decision 404). If it is determined that the OTA capacity is limiting the throughput (‘yes’ at decision 404), the small cell base station via operation of BALM component 324 may take remedial actions to relieve the congestion on its air link, e.g., marking the UE as a candidate for handout to, e.g., a macro cell base station (block 406). In an alternate aspect, if it is determined that it is not the OTA capacity that is limiting the throughput (‘no’ at decision 404), the small cell base station via operation of BALM component 324 may perform a per-user rate shaping procedure and determine if other UEs being served by the small cell base station are limiting backhaul throughput (decision 408). In an additional aspect, if it is determined that other UEs being served by the small cell base station are limiting the backhaul throughput (‘yes’ at decision 408), the small cell base station via operation of BALM component 324 may take remedial actions, e.g., marking the user equipment as a candidate for handout to a macro cell base station (block 406).

In an aspect, if it is determined that the other UEs being served by the small cell base station are not limiting the backhaul throughput (‘no’ at decision 408), the small cell base station via operation of BALM component 324 may perform a light active estimation procedure (for example, estimation of backhaul state using actively-induced packets with small overhead or naturally-induced/occurring packets whose statistical characteristics make them a good replacement for actively-induced packets for light active estimation, which are typically used to directly measure backhaul latency and loss) to determine if the Internet service provider (ISP) queue is fully utilized (decision 410). If it is determined that the ISP queue does not appear to be full (‘no’ at decision 410), there may be no backhaul capacity problem and the small cell base station via operation of BALM component 324 may revert to performing light passive estimation monitoring as appropriate, as described above. In an alternative aspect, if it is determined that the ISP queue does appear to be full (‘yes’ at decision 410), there may be a backhaul capacity problem and the small cell base station via operation of BALM component 324 may further perform a heavy active estimation procedure (e.g., estimation of backhaul state using actively-induced packets with potentially high overhead, or naturally-induced/occurring packets whose statistical characteristics make them a good replacement for actively-induced packets for heavy active estimation, which are typically used to directly measure throughput) to determine if the throughput is being limited by congestion at the Internet peer with which the UE is communicating, rather than by the backhaul link itself (decision 412).

In an aspect, if it is determined that throughput is not being limited by congestion at the Internet peer with which the UE is communicating (‘no’ at decision 412), the small cell base station via operation of BALM component 324 may determine that there is a backhaul capacity problem and may take remedial actions, e.g., marking the UE as a candidate for handout to a macro cell base station (block 406). In an alternative aspect, if it is determined that the throughput is being limited by congestion at the Internet peer with which the UE is communicating (‘no’ at decision 412), there may be no backhaul capacity problem and the small cell base station via operation of BALM component 324 may revert to performing light passive estimation monitoring as appropriate, as described above.

In an aspect, in order to optimize BALM component 324 and the different BALM related procedures in FIG. 4, the small cell base station via operation of BALM component 324 may perform various calibration procedures on a continual, periodic, and/or or an event-driven basis. For example, different backhaul networks may experience congestion differently, e.g., at least in part due to the different subscription policies and schedulers used by the different ISPs to implement their respective networks. Additionally, small cell base stations are typically blind to the particular ISP implementations and pre-configurations to accommodate all potential variations would be exhaustive if not prohibitive. Accordingly, a small cell base station operating BALM component 324 configured to perform BALM related procedures as described above may be further configured to calibrate the procedures by determining, e.g., in an automated manner, various parameters related to the backhaul implementation (“backhaul parameters”) in which the small cell base station is deployed.

FIG. 5 is a flow diagram 500 illustrating an example method in an aspect of the passive estimation operation of BALM component 324 for backhaul management at a small cell base station.

In an aspect, at block 510, methodology 500 may include determining, at the small cell base station, whether a time slot utilization of a flow (e.g., transmission control protocol (TCP) flow between the small cell base station 320 and UE 322) at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow. For example, in an aspect, small cell base station 320 and/or BALM component 324 may include a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to determine whether time slot utilization of a flow at UE 322 which is in communication with small cell base station 320 is above a first threshold.

In an aspect, the UE may have one or more multiple flows. For example, in an aspect, the time slot utilization may be determined for each flow of the UE if the UE has multiple flows. In an additional aspect, the time slot utilization may be determined together for all the flows at the UE. Additionally, in an aspect, the time slot utilization may be determined based on the direction of a flow, for example, a down link (DL) or a uplink (UL), or a combination of both. For example, the DL flow is from base station 320 to UE 322 and/or the UL flow is from UE 322 to small cell base station 320. In an additional or an optional aspect, a combination of the various aspects (e.g., flows, directions, etc.) may be used for calculating time slot utilization.

In an aspect, the time slot utilization may be determined based on the number of scheduling opportunities used by a flow at UE 322 and/or by all the flows at the UE. For example, time slot utilization can be determined based on the number of scheduling opportunities that are allocated and the number of scheduling opportunities that are utilized. As described above, this may be on a per flow or per UE basis. Thus, persons skilled in the art will appreciate that although a flow is used herein as an example for describing the passive estimation mechanism for backhaul management at the small cell base station, the passive estimation mechanism can apply similarly at a UE level as well (e.g., a UE with multiple flows) and/or in one or both directions (e.g., UL and/or DL).

In an aspect, when BALM component 324 determines the time slot utilization, the time slot utilization may be identified, for example, as “low” or “high.” For example, in an aspect, the time slot utilization may be identified as low when BALM component 324 determines that the time slot utilization is below a threshold (e.g., a first threshold) and/or the time slot utilization may be identified as high when the BALM component 324 determines that the time slot utilization is above the threshold (e.g., the first threshold). In an additional or optional aspect, BALM component 324 may determine whether the time slot utilization is above/below the first threshold based on whether the time slot utilization is above/below the first threshold for a period of time (e.g., a time to trigger (TTT)) and/or by a certain amount (e.g., a hysteresis). For example, in an aspect, time slot utilization may be considered to be above the first threshold value when the time slot utilization is above the first threshold value plus a margin of 10% for a period of 1 second.

In a further additional or optional aspect, BALM component 324 may configure the initial slot utilization as low. For example, in an aspect, the first threshold may be a fixed value (e.g., 80% of slots are utilized), a function of the network protocol (e.g., video vs VoIP), or a function of the normally-desired threshold and the time elapsed since the start of the flow (e.g., the threshold may be 0% for the first 30 seconds of the flow, or may be increasing linearly between 0% and 100% for the first 30 seconds of the flow, or may be a stepwise linear function such as 95% the first 15 seconds of the flow, 90% the second 15 second interval in the flow and 80% thereafter to the end of the flow).

In an aspect, when BALM component 324 determines that the slot utilization is below the first threshold, the flow or UE may be considered as “satisfied” (e.g., not limited by backhaul of the small cell base station) and there may be no need for determining the average throughput values. In an aspect, when BALM component 324 determines that the slot utilization is above the first threshold, the flow or UE may be considered to be using most (e.g., majority, all, etc.) of the scheduling opportunities and its ability to schedule more data may be limited by the available backhaul.

In an aspect, at block 520, methodology 500 may include determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold. For example, in an aspect, small cell base station 320 and/or BALM component 324 may include a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to determine whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold. In an additional or optional aspect, BALM component 324 may calculate the average throughput on the basis of a flow, UE, direction, and/or a combination.

In an aspect, for example, when BALM component 324 determines that the slot utilization is high (e.g., for a flow and/or UE), BALM component 324 may compare average throughput (e.g., of the flow and/or UE) with a threshold (e.g., second threshold) to determine whether the average throughput of the flow is below the second threshold.

In an aspect, BALM component 324 may compute average throughput (e.g., primitive throughput) based on average number of bits received per time slot over several time slots. For example, average throughput in a time slot may be calculated by computing the number of bits received during a one minute time interval divided by the number of time slots (e.g., by dividing number of bits received during one minute interval by 20 with each time slot configured for 50 ms). When BALM component 324 determines that the average throughput is below the threshold, the time slot may be considered as an idle time slot. In an additional or optional aspect, BALM component 324 may average throughput over all slots in the high slot utilization time interval, or only over the active slots in the high slot utilization interval (e.g., perceived throughput).

In an additional or optional aspect, BALM component 324 may compute average throughput by taking into consideration packet headers (e.g., TCP/IP headers) or protocol control packets (e.g., UDP, Skype, etc). In a further additional aspect, BALM component 324 may compute average throughput by taking into consideration a statistical function, e.g., a tail or a combination of bits in several time slots. In an additional aspect, BALM component 324 may compute average throughput (e.g., perceived throughout) based on whether the number of bits received during slow_start_time of a flow is higher than a threshold value (e.g., bit active threshold) and/or the time since the idle state is above a threshold value (e.g., time_active_threshold).

For example, in an aspect, the second threshold may be a fixed value (e.g., 5 Mbps), a function of the network protocol (e.g., video vs VoIP), or a function of a nominally desired threshold and the time elapsed since the start of the high slot utilization interval (e.g., the threshold may be 0 Mbps for the first 30 seconds, or may be increasing linearly between 0% and 100% of the desired threshold for the first 30 seconds of the flow, or may be a stepwise linear function such as 95% of the desired threshold the first 15 seconds of the flow, 90% of the desired threshold the second 15 second interval in the flow and 80% of the desired threshold thereafter to the end of the high slot utilization interval).

In an additional aspect, when BALM component 324 identifies a time slot as not being an idle time slot, the time slot may be considered as an active time slot. However, certain exceptions may have to be taken into consideration due to TCP/IP behavior. For example, the TCP protocol has three states—idle, slow start state, and congestion avoidance state. During the slow start state, the protocol is trying to determine the appropriate throughput. That is, the flow has not yet converged to an average throughput or steady-state oscillations centered about an average throughput. Therefore, in an aspect, the duration of slow start state (e.g., slow_start_time) may not be taken into consideration when computing the average throughput. For example, the time slot may be considered as an active time slot if the time since the idle time slot has passed is above some threshold value (e.g., a threshold timer).

However, in certain scenarios, BALM component 324 may not necessarily wait until the above threshold timer has passed. For example, in an aspect, BALM component 324 may consider a time slot as an active time slot if the average number of bits received during the slow start time is above a threshold. For example, the threshold(s) related to the protocol behavior may be configured directly or derived from the time it takes for a TCP flow to reach minimum throughput with some assumed, configured, or directed RTT, plus some safety margin. In an aspect, RTT may be calculated from TCP handshake RTT observation, and enhanced by subsequent RTT observations.

In an aspect, at block 530, methodology 500 may include identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold. For example, in an aspect, small cell base station 320 and/or BALM component 324 may include a specially programmed processor module, or a processor executing specially programmed code stored in a memory, to identify that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

In an additional or optional aspect, small cell base station 320 and/or BALM component 324 may be configured to perform bandwidth throttling when backhaul congestion is detected regardless of UE satisfaction. For example, BALM component 324 may limit the small cell base station throughput to ensure, for example, a minimal capacity guarantee for cross-traffic. In an aspect, the throughput limitation can be applied in the congestion direction, or in the other direction (e.g., limit uplink so that downlink throughput is not impacted by delayed/dropped uplink TCP ACKs). In an aspect, for example, BALM component 324 may perform bandwidth throttling at a fixed bandwidth, a fixed percentage of the available bandwidth, a variable percentage of the available bandwidth as determined during calibration, or in proportion to the bandwidth that each of the UEs are utilizing.

In an aspect, for example, BALM component 324 may perform bandwidth throttling on all UEs to ensure that a total link throughput is capped at a desired level. Alternatively or additionally, only a number of selected UEs may be throttled, e.g., the UEs with the highest throughput (based on the quality of throughput). Alternatively or additionally, only non-member UEs (based on membership) may be throttled. Alternatively or additionally, a number of selected flows may be throttled. For example, VOIP flows may be excluded from throttling (throttling based on the type of traffic), or high-performing UEs may be exclude from throttling (throttling based on the quality of throughput).

In some aspects, BALM component 324 may perform hybrid throttling by throttling the throughput of each UE and/or flow at a certain level, while performing additional throttling of all UEs (or selected flows) to ensure that the link throughput is maintained at a desired level.

FIG. 6 illustrates an aspect of the configuration of BALM component 324 in an example small cell base station 600 for passive estimation mechanism for backhaul management at a small cell base station. In this example, the small cell base station 600 is deployed in the vicinity of one or more client devices 640, such as the UEs 322 in FIG. 3, and a router 630 providing Internet access, such as the home router 302 in FIG. 3. It should be noted that BALM component 324 may include all or some portion of the following, or may include a separate portion of some of these components that are in communication with remaining ones of these components.

In general, the small cell base station 600 and/or BALM component 324 includes various components for providing and processing services for the client devices 640. For example, the small cell base station 600 may include a transceiver 612 for wireless communication with the one or more of the clients 640 and a backhaul controller 614 for backhaul communications with other network devices, such as the router 630. These components may operate under the direction of a processor 616 in conjunction with memory 618, for example, all of which may be interconnected via a bus 620 or the like.

In addition and in accordance with the discussion above, the small cell base station 600 and/or BALM component 324 may also further include a time slot utilization determiner 622 for determining whether a time slot utilization of a flow at a user equipment (UE) is above a first threshold, an average throughout determiner 624 for determining whether an average throughput of the flow is above a second threshold, and/or a flow satisfaction determiner 626 for identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.

FIG. 7 illustrates in more detail the principles of wireless communication between a wireless device 710 (e.g., small cell base station 320 of FIG. 3), including BALM component 324, and a wireless device 750 (e.g., UE 322 of FIG. 3) of a sample communication system 700 that may be adapted as described herein. In an aspect, the functionality of BALM component 324 may be in one or more modules or instructions within processor 730, or within computer readable instructions stored in memory 732 and executable by processor 730, or some combination of both.

At the device 710, traffic data for a number of data streams is provided from a data source 712 to a transmit (TX) data processor 914. Each data stream may then be transmitted over a respective transmit antenna.

The TX data processor 714 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data. The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by a processor 730. A data memory 732 may store program code, data, and other information used by the processor 730 or other components of the device 710.

The modulation symbols for all data streams are then provided to a TX MIMO processor 720, which may further process the modulation symbols (e.g., for OFDM). The TX MIMO processor 720 then provides NT modulation symbol streams to NT transceivers (XCVR) 722A through 722T. In some aspects, the TX MIMO processor 720 applies beam-forming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transceiver 722 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. NT modulated signals from transceivers 722A through 722T are then transmitted from NT antennas 724A through 724T, respectively.

At the device 750, the transmitted modulated signals are received by NR antennas 752A through 752R and the received signal from each antenna 752 is provided to a respective transceiver (XCVR) 754A through 754R. Each transceiver 754 conditions (e.g., filters, amplifies, and down converts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

A receive (RX) data processor 760 then receives and processes the NR received symbol streams from NR transceivers 754 based on a particular receiver processing technique to provide NT “detected” symbol streams. The RX data processor 760 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by the RX data processor 760 is complementary to that performed by the TX MIMO processor 720 and the TX data processor 714 at the device 710.

A processor 770 periodically determines which pre-coding matrix to use (discussed below). The processor 770 formulates a reverse link message comprising a matrix index portion and a rank value portion. A data memory 772 may store program code, data, and other information used by the processor 770 or other components of the device 750.

The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 738, which also receives traffic data for a number of data streams from a data source 736, modulated by a modulator 780, conditioned by the transceivers 754A through 754R, and transmitted back to the device 710.

At the device 710, the modulated signals from the device 750 are received by the antennas 724, conditioned by the transceivers 722, demodulated by a demodulator (DEMOD) 740, and processed by a RX data processor 742 to extract the reverse link message transmitted by the device 750. The processor 730 then determines which pre-coding matrix to use for determining the beam-forming weights then processes the extracted message.

FIG. 7 also illustrates that the communication components may include one or more components that perform backhaul management at a small cell base station as taught herein. For example, a communication (COMM.) component 790 may cooperate with the processor 730 and/or other components of the device 710 to perform the calibration as taught herein. Similarly, a communication control component 792 may cooperate with the processor 770 and/or other components of the device 750 to support the configuration as taught herein. It should be appreciated that for each device 710 and 750 the functionality of two or more of the described components may be provided by a single component. For example, a single processing component may provide the functionality of the communication control component 790 and the processor 730 and a single processing component may provide the functionality of the communication control component 792 and the processor 770.

FIG. 8 illustrates an example small cell base station apparatus 800, including BALM component 324, represented as a series of interrelated functional modules. In an aspect, small cell base station apparatus 800 and/or BALM component 324 may include a module for determining a time slot utilization 802, a module for determining an average throughput 804, and a module for identifying 806 that may correspond at least in some aspects to, for example, a processing system as discussed herein.

The functionality of the modules of FIG. 8 may be implemented in various ways consistent with the teachings herein. In some aspects, the functionality of these modules may be implemented as one or more electrical components. In some aspects, the functionality of these blocks may be implemented as a processing system including one or more processor components. In some aspects, the functionality of these modules may be implemented using, for example, at least a portion of one or more integrated circuits (e.g., an ASIC). As discussed herein, an integrated circuit may include a processor, software, other related components, or some combination thereof. Thus, the functionality of different modules may be implemented, for example, as different subsets of an integrated circuit, as different subsets of a set of software modules, or a combination thereof. Also, it should be appreciated that a given subset (e.g., of an integrated circuit and/or of a set of software modules) may provide at least a portion of the functionality for more than one module.

In addition, the components and functions represented by FIG. 8 as well as other components and functions described herein, may be implemented using any suitable means. Such means also may be implemented, at least in part, using corresponding structure as taught herein. For example, the components described above in conjunction with the “module for” components of FIG. 8 also may correspond to similarly designated “means for” functionality. Thus, in some aspects one or more of such means may be implemented using one or more of processor components, integrated circuits, or other suitable structure as taught herein.

In some aspects, an apparatus or any component of an apparatus may be configured to (or operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.

Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

Accordingly, an aspect disclosed can include a computer readable media embodying a method for calibrating a small cell base station for management of a backhaul link to an ISP. Accordingly, the invention is not limited to illustrated examples and any means for performing the functionality described herein are included in aspects disclosed.

While the foregoing disclosure shows illustrative aspects disclosed, it should be noted that various changes and modifications could be made herein without departing from the scope of the invention as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects described herein need not be performed in any particular order. Furthermore, although elements disclosed may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium. The computer-readable medium may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., compact disk (CD), digital versatile disk (DVD)), a smart card, a flash memory device (e.g., card, stick, key drive), random access memory (RAM), read only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer.

The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium may be resident in the processing system, external to the processing system, or distributed across multiple entities including the processing system. The computer-readable medium may be embodied in a computer-program product. By way of example, a computer-program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” 

What is claimed is:
 1. A method for passive estimation mechanism for backhaul management at a small cell base station, comprising: determining, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow; determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold; and identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.
 2. The method of claim 1, further comprising: determining whether to handout the UE to another base station based on identifying that the flow is not satisfied.
 3. The method of claim 1, further comprising: determining the time slot utilization of the flow by computing a number of scheduling opportunities used by the flow.
 4. The method of claim 1, wherein determining whether the time slot utilization of the flow is above the first threshold includes: comparing the number of scheduling opportunities used by the flow with the first threshold value.
 5. The method of claim 1, wherein determining whether the time slot utilization of the flow is above the first threshold includes: determining whether the time slot utilization of the flow is above the first threshold for a first duration.
 6. The method of claim 1, wherein determining the average throughput of the flow includes: computing an average number of bits received in a time slot by averaging total number of bits received during a plurality of time slots.
 7. The method of claim 1, wherein determining the average throughput of the flow includes: computing the average throughput of the flow when the time slot is in an active state.
 8. An apparatus for passive estimation mechanism for backhaul management at a small cell base station, comprising: means for determining, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow; means for determining whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold; and means for identifying that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.
 9. The apparatus of claim 8, further comprising: means for determining whether to handout the UE to another base station based on identifying that the flow is not satisfied.
 10. The apparatus of claim 8, further comprising: means for determining the time slot utilization of the flow by computing a number of scheduling opportunities used by the flow.
 11. The apparatus of claim 8, wherein means for determining whether the time slot utilization of the flow is above the first threshold includes: means for comparing the number of scheduling opportunities used by the flow with the first threshold value.
 12. The apparatus of claim 8, wherein means for determining whether the time slot utilization of the flow is above the first threshold includes: means for determining whether the time slot utilization of the flow is above the first threshold for a first duration.
 13. The apparatus of claim 8, wherein means for determining the average throughput of the flow includes: means for computing an average number of bits received in a time slot by averaging total number of bits received during a plurality of time slots.
 14. The apparatus of claim 8, wherein means for determining the average throughput of the flow includes: means for computing the average throughput of the flow when the time slot is in an active state.
 15. A non-transitory computer readable medium for passive estimation mechanism for backhaul management at a small cell base station comprising code that, when executed by a processor or processing system included within the small cell base station, causes the small cell base station to: determine, at the small cell base station, whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow; determine whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold; and identify that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.
 16. The computer readable medium of claim 15, further comprising: code for determining whether to handout the UE to another base station based on identifying that the flow is not satisfied.
 17. The computer readable medium of claim 15, further comprising: code for determining the time slot utilization of the flow by computing a number of scheduling opportunities used by the flow.
 18. The computer readable medium of claim 15, wherein the code for determining whether the time slot utilization of the flow is above the first threshold includes: code for comparing the number of scheduling opportunities used by the flow with the first threshold value.
 19. The computer readable medium of claim 15, wherein the code for determining whether the time slot utilization of the flow is above the first threshold includes: code for determining whether the time slot utilization of the flow is above the first threshold for a first duration.
 20. The computer readable medium of claim 15, wherein the code for determining the average throughput of the flow includes: code for computing an average number of bits received in a time slot by averaging total number of bits received during a plurality of time slots.
 21. The computer readable medium of claim 15, wherein the code for determining the average throughput of the flow includes: code for computing the average throughput of the flow when the time slot is in an active state.
 22. An apparatus for passive estimation mechanism for backhaul management at a small cell base station, comprising: a time slot utilization determiner to determine whether a time slot utilization of a flow at a user equipment (UE) in communication with the small cell base station is above a first threshold, wherein a plurality of time slots are associated with the flow; an average throughout determiner to determine whether an average throughput of the flow is below a second threshold in response to determining that the time slot utilization is above the first threshold; and a flow satisfaction identifier to identify that the flow is not satisfied in response to determining that the average throughput of the flow is below the second threshold.
 23. The apparatus of claim 22, wherein the time slot utilization determiner is further configured to: determine the time slot utilization of the flow by computing a number of scheduling opportunities used by the flow.
 24. The apparatus of claim 22, wherein the time slot utilization determiner is further configured to: compare the number of scheduling opportunities used by the flow with the first threshold value.
 25. The apparatus of claim 22, wherein the time slot utilization determiner is further configured to: determine whether the time slot utilization of the flow is above the first threshold for a first duration.
 26. The apparatus of claim 22, wherein the average throughout determiner is further configured to: compute an average number of bits received in a time slot by averaging total number of bits received during a plurality of time slots.
 27. The apparatus of claim 22, wherein the average throughout determiner is further configured to: compute the average throughput of the flow when the time slot is in an active state. 